The invention relates to a method for filling up a storage tank with a gaseous, pressurized medium, in particular hydrogen, as well as to a fueling facility for filling up a storage tank with such a medium.
Vehicles that take gaseous hydrogen as a fuel require specially designed fueling facilities, which guide the hydrogen into the storage tank of the vehicle, which in this case is also referred to as a vehicle tank. Such a fueling facility or gas station usually exhibits a tank with liquid hydrogen or is hooked up directly to a hydrogen pipeline or other systems that can provide hydrogen. Since the hydrogen for fueling is to be present in the gaseous phase, such a fueling facility usually has a gas buffer tank, which is supplied by the aforementioned (liquid hydrogen) tank and holds the gaseous hydrogen available.
Standard SAE J2601 was created to ensure safety (explosion risk) for the environment when filling up hydrogen tanks (e.g., vehicle tanks) with hydrogen and provide a standard for the fueling process. Among other things, the standard places safety-related limits and performance requirements on the fueling process. SAE J2601 provides that hydrogen-powered vehicles can be refueled within three minutes, without the temperature of the hydrogen rising to above a temperature of 85° C. in the process. At the same time, it requires that the temperature of the hydrogen not exceed −40° C. while fueling as it enters the storage tank. There are also rules that govern permitted temperature fluctuations while fueling.
In order not to exceed the maximum permissible temperature of 85° C. while fueling or drop below the limited precooling of the hydrogen to −40° C., the temperature of the hydrogen for filling up a storage tank must thus among other things be brought to a comparatively narrow temperature range of −33 to −40° C., preferably within 25 s.
Given the changing temperature conditions in the pipelines, it is comparatively complicated and cost-intensive to realize a constant temperature for the hydrogen (e.g., of −40°) at the gas pump. Among other things, this is because the tank feed line temperature comes to approximate the ambient temperature once a fueling process has ended. An excessively heated tank feed line can thus keep the hydrogen at the gas pump from reaching the prescribed temperature range of −33 to −40° C. within a set period of time, so that the fueling process must be interrupted.
In order to prevent this, long tank feed lines require that the tank feed line be cooled, or a cooling device that is positioned as close as possible to the fueling nozzle to the storage tank. However, cooling the tank feed line is associated with high costs, and a cooling device on the fueling nozzle must be provided with all the cooling capacity required, which in turn makes the cooling device and connecting lines significantly more expensive.
Proceeding from the above, the object of the present invention is to provide a method of the type mentioned above, in which the tank line can be quickly and comparatively inexpensively cooled in such a way that the hydrogen exhibits the target temperature while being introduced into the storage tank or vehicle tank.